1. Field of the Invention
The invention is directed to information systems, and more particularly, to determining the viability of hypertext links in a network, such as the World Wide Web.
2. Description of Related Art
Large information networks, such as the World Wide Web are well-known in the art. Documents stored in such an information system contain information links, such as hypertext links, to related information.
The Problems
Navigating through information space in network information systems such as the World Wide Web (the web) by using such links can be a frustrating experience because the web is a dynamic environment where documents are frequently moved, outdating the network addresses pointed to by some information links. Further, some network components, such as servers or pointers, may be temporarily or permanently out of service. Rather than connecting a user to a network address, such as URL (Universal Resource Locator) every time the link is attempted, not infrequently an error message, such as "ERROR 404, file not found", is generated when users click on a link that does not work. Users have no way of telling if the link is temporarily disabled (due to network traffic, web site updates, etc.) or permanently disabled due to a web page that has moved or been shut down. Understanding the differences between temporary and permanent disablement is important in order to know if the user can profitably return to the desired site at a later time. Unfortunately, users have no way of knowing this information with current techniques.
Web site creators have little incentive to continually update links they list or to take down old web pages. Therefore, network users are likely to encounter more and more outdated web pages with links that never work.
Unpredictability of web links leads to a lower-quality experience when people use the web. If users start perceiving the web as unpredictable or as a ghost-town, users may be less inclined to seek information through the web. The prior art provides only a binary indication whether a link is broken or viable. There is thus a need for a way for web users to know the probability that a given web link will work, and a method for rating web pages based on the viability of the links on the page.